More likely then not you will come to find problems arising that aren't laid out on paper. 

Gasoline prices have not stopped rising in recent weeks in California due to the high demand, a common phenomenon at this time of year in the state (compounded by the urgency of nearly everybody to go somewhere, anywhere, now that the pandemic is unwinding).

A token can represent 1) an equity interest in a legal entity that owns that real estate property 2) a right to share in profits arising from the use of the asset 3) ownership of the underlying asset or 4) an interest in a debt secured by the asset.

Should an unexpected financial issue arise, guess who will be at the bottom of the list to pay that month. . .good ol' cousin Ryan.

If you are getting 15-20% IRR (which is fairly common) then you will be set up pretty well to keep growing your wealth 100% passively. 

In general what are common timelines for purchase to close?.

Is this common?

The standard brick side-by-side thats so common around here.

When we do our estimates, if we don't know the exact land value, it is common to use 80/20 for estimates only.

It's pretty common here at most price points.